Community SARS-CoV-2 Surge and Within-School Transmission

OBJECTIVES

When the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic began, experts raised concerns about in-person instruction in the setting of high levels of community transmission. We describe secondary transmission of SARS-CoV-2 within North Carolina kindergarten through 12th-grade school districts during a winter surge to determine if mitigation strategies can hinder within-school transmission.

METHODS

From October 26, 2020, to February 28, 2021, 13 North Carolina school districts participating in The ABC Science Collaborative were open for in-person instruction, adhered to basic mitigation strategies, and tracked community- and school-acquired SARS-CoV-2 cases. Public health officials adjudicated each case. We combined these data with that from August 2020 to evaluate the effect of the SARS-CoV-2 winter surge on infection rates as well as weekly community- and school-acquired cases. We evaluated the number of secondary cases generated by each primary case as well as the role of athletic activities in school-acquired cases.

RESULTS

More than 100 000 students and staff from 13 school districts attended school in person; of these, 4969 community-acquired SARS-CoV-2 infections were documented by molecular testing. Through contact tracing, North Carolina local health department staff identified an additional 209 infections among >26 000 school close contacts (secondary attack rate <1%). Most within-school transmissions in high schools (75%) were linked to school-sponsored sports. School-acquired cases slightly increased during the surge; however, within-school transmission rates remained constant, from presurge to surge, with ∼1 school-acquired case for every 20 primary cases.

CONCLUSIONS

With adherence to basic mitigation strategies, within-school transmission of SARS-CoV-2 can be interrupted, even during a surge of community infections.

Risk of infection and transmission of SARS-CoV-2 among children and adolescents in households, communities and educational settings: A systematic review and meta-analysis

BACKGROUND

There is uncertainty with respect to SARS-CoV-2 transmission in children (0-19 years) with controversy on effectiveness of school-closures in controlling the pandemic. It is of equal importance to evaluate the risk of transmission in children who are often asymptomatic or mildly symptomatic carriers that may incidentally transmit SARS-CoV-2 in different settings. We conducted this review to assess transmission and risks for SARS-CoV-2 in children (by age-groups or grades) in community and educational-settings compared to adults.

METHODS

Data for the review were retrieved from PubMed, EMBASE, Cochrane Library, WHO COVID-19 Database, China National Knowledge Infrastructure (CNKI) Database, WanFang Database, Latin American and Caribbean Health Sciences Literature (LILACS), Google Scholar, and preprints from medRixv and bioRixv) covering a timeline from December 1, 2019 to April 1, 2021. Population-screening, contact-tracing and cohort studies reporting prevalence and transmission of SARS-CoV-2 in children were included. Data were extracted according to PRISMA guidelines. Meta-analyses were performed using Review Manager 5.3.

RESULTS

Ninety studies were included. Compared to adults, children showed comparable national (risk ratio (RR) = 0.87, 95% confidence interval (CI) = 0.71-1.060 and subnational (RR = 0.81, 95% CI = 0.66-1.01) prevalence in population-screening studies, and lower odds of infection in community/household contact-tracing studies (odds ratio (OR) = 0.62, 95% CI = 0.46-0.84). On disaggregation, adolescents observed comparable risk (OR = 1.22, 95% CI = 0.74-2.04) with adults. In educational-settings, children attending daycare/preschools (OR = 0.53, 95% CI = 0.38-0.72) were observed to be at lower-risk when compared to adults, with odds of infection among primary (OR = 0.85, 95% CI = 0.55-1.31) and high-schoolers (OR = 1.30, 95% CI = 0.71-2.38) comparable to adults. Overall, children and adolescents had lower odds of infection in educational-settings compared to community and household clusters.

CONCLUSIONS

Children (<10 years) showed lower susceptibility to COVID-19 compared to adults, whereas adolescents in communities and high-schoolers had comparable risk. Risks of infection among children in educational-settings was lower than in communities. Evidence from school-based studies demonstrate it is largely safe for children (<10 years) to be at schools, however older children (10-19 years) might facilitate transmission. Despite this evidence, studies focusing on the effectiveness of mitigation measures in educational settings are urgently needed to support both public health and educational policy-making for school reopening.

Continental transmission of emerging COVID-19 on the 38° north latitude

BACKGROUND

As COVID-19 has become a pandemic emerging infectious disease it is important to examine whether there was a spatiotemporal clustering phenomenon in the globe during the rapid spread after the first outbreak reported from southern China.

MATERIALS AND METHODS

The open data on the number of COVID-19 cases reported at daily basis form the globe were used to assess the evolution of outbreaks with international air link on the same latitude and also including Taiwan. The dynamic Susceptible-Infected-Recovered model was used to evaluate continental transmission from December 2019 to March 2020 before the declaration of COVID-19 pandemic with basic reproductive number and effective reproductive number before and after containment measurements.

RESULTS

For the initial COVID-19 outbreak in China, the estimated reproductive number was reduced from 2.84 during the overwhelming outbreaks in early January to 0.43 after the strict lockdown policy. It is very surprising to find there were three countries (including South Korea, Iran, and Italy) and the Washington state of the USA on the 38° North Latitude involved with large-scale community-acquired outbreaks since the first imported COVID-19 cases from China. The propagation of continental transmission was augmented from hotspot to hotspot with higher reproductive number immediately before the declaration of pandemic. By contrast, there was not any large community-acquired outbreak in Taiwan.

CONCLUSION

The propagated spatiotemporal transmission from China to other hotspots may explain the emerging pandemic that can only be exempted by timely border control and preparedness of containment measurements according to Taiwan experience.

Summary of Guidance for Public Health Strategies to Address High Levels of Community Transmission of SARS-CoV-2 and Related Deaths, December 2020

In the 10 months since the first confirmed case of coronavirus disease 2019 (COVID-19) was reported in the United States on January 20, 2020 (1), approximately 13.8 million cases and 272,525 deaths have been reported in the United States. On October 30, the number of new cases reported in the United States in a single day exceeded 100,000 for the first time, and by December 2 had reached a daily high of 196,227.* With colder weather, more time spent indoors, the ongoing U.S. holiday season, and silent spread of disease, with approximately 50% of transmission from asymptomatic persons (2), the United States has entered a phase of high-level transmission where a multipronged approach to implementing all evidence-based public health strategies at both the individual and community levels is essential. This summary guidance highlights critical evidence-based CDC recommendations and sustainable strategies to reduce COVID-19 transmission. These strategies include 1) universal face mask use, 2) maintaining physical distance from other persons and limiting in-person contacts, 3) avoiding nonessential indoor spaces and crowded outdoor spaces, 4) increasing testing to rapidly identify and isolate infected persons, 5) promptly identifying, quarantining, and testing close contacts of persons with known COVID-19, 6) safeguarding persons most at risk for severe illness or death from infection with SARS-CoV-2, the virus that causes COVID-19, 7) protecting essential workers with provision of adequate personal protective equipment and safe work practices, 8) postponing travel, 9) increasing room air ventilation and enhancing hand hygiene and environmental disinfection, and 10) achieving widespread availability and high community coverage with effective COVID-19 vaccines. In combination, these strategies can reduce SARS-CoV-2 transmission, long-term sequelae or disability, and death, and mitigate the pandemic's economic impact. Consistent implementation of these strategies improves health equity, preserves health care capacity, maintains the function of essential businesses, and supports the availability of in-person instruction for kindergarten through grade 12 schools and preschool. Individual persons, households, and communities should take these actions now to reduce SARS-CoV-2 transmission from its current high level. These actions will provide a bridge to a future with wide availability and high community coverage of effective vaccines, when safe return to more everyday activities in a range of settings will be possible.

Risk Perception of COVID-19 Community Transmission among the Spanish Population

On 11 March 2020 the SARS-CoV-2 virus was officially declared a pandemic and measures were set up in various countries to avoid its spread among the population. This paper aims to analyse the perception of risk of COVID-19 infection in the Spanish population. A cross-sectional, descriptive observational study was conducted with a total of 16,372 Spanish participants. An online survey was used to gather data for 5 consecutive days over the compulsory lockdown period which was established after the state of emergency was declared. There is an association between socio-demographic variables and risk perception, and a very strong relationship between this perception and contact and direct experience with the virus in a family, social or professional setting. We also found that compared to working from home, working outside the home increased the perception of risk of infection and the perception of worsening health. Understanding the public perception of the risk of COVID-19 infection is fundamental for establishing effective prevention measures.

Secondary attack rate of COVID-19 in household contacts: a systematic review

Coronavirus disease 2019 (COVID-19) is a novel virus with continuously evolving transmission trends. Contact tracing and quarantining of positive cases are chief strategies of disease control that has been accepted globally, though scientific knowledge regarding household transmission of the COVID-19 through contact of positive case is sparse. Current systematic review was planned to assess global statistics and characteristics of household secondary attack rate (SAR) of COVID-19. Eligible articles were retrieved through search of-MEDLINE, SCOPUS and EMBASE for the period December 2019 to 15 June 2020. Search terms were developed to identify articles reporting household SARs in various countries. After initial screening of 326 articles, 13 eligible studies were included in the final evidence synthesis. We found that SAR varies widely across countries with lowest reported rate as 4.6% and highest as 49.56%. The rates were unaffected by confounders such as population of the country, lockdown status and geographic location. Review suggested greater vulnerability of spouse and elderly population for secondary transmission than other household members. It was also observed that quarantining and isolation are most effective strategies for prevention of the secondary transmission of the disease. Symptomatic status of the index case emerged to be a critical factor, with very low transmission probability during asymptomatic phase. Present review findings recommend that adequate measures should be provided to protect the vulnerable population as only case tracing and quarantining might be insufficient. It should be combined with advisory for limiting household contacts and active surveillance for symptom onset.

Characteristics of Household Transmission of COVID-19

BACKGROUND

Since December 2019, SARS-CoV-2 has extended to most parts of China with >80 000 cases and to at least 100 countries with >60 000 international cases as of 15 March 2020. Here we used a household cohort study to determine the features of household transmission of COVID-19.

METHODS

A total of 105 index patients and 392 household contacts were enrolled. Both index patients and household members were tested by SARS-CoV-2 RT-PCR. Information on all recruited individuals was extracted from medical records and confirmed or supplemented by telephone interviews. The baseline characteristics of index cases and contact patients were described. Secondary attack rates of SARS-CoV-2 to contact members were computed and the risk factors for transmission within the household were estimated.

RESULTS

Secondary transmission of SARS-CoV-2 developed in 64 of 392 household contacts (16.3%). The secondary attack rate to children was 4% compared with 17.1% for adults. The secondary attack rate to the contacts within the households with index patients quarantined by themselves since onset of symptoms was 0% compared with 16.9% for contacts without quarantined index patients. The secondary attack rate to contacts who were spouses of index cases was 27.8% compared with 17.3% for other adult members in the households.

CONCLUSIONS

The secondary attack rate of SARS-CoV-2 in household is 16.3%. Age of household contacts and spousal relationship to the index case are risk factors for transmission of SARS-CoV-2 within a household. Quarantine of index patients at home since onset of symptoms is useful to prevent the transmission of SARS-Co-2 within a household.

Tracking the onset date of the community spread of SARS-CoV-2 in western countries

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the world during 2020, but the precise time in which the virus began to spread locally is difficult to trace for most countries. Here, we estimate the probable onset date of the community spread of SARS-CoV-2 for heavily affected countries from Western Europe and the Americas on the basis of the cumulative number of deaths reported during the early stage of the epidemic. Our results support that SARS-CoV-2 probably started to spread locally in all western countries analysed between mid-January and mid-February 2020, thus long before community transmission was officially recognised and control measures were implemented.

Effective control of SARS-CoV-2 transmission between healthcare workers during a period of diminished community prevalence of COVID-19

Previously, we showed that 3% (31/1032)of asymptomatic healthcare workers (HCWs) from a large teaching hospital in Cambridge, UK, tested positive for SARS-CoV-2 in April 2020. About 15% (26/169) HCWs with symptoms of coronavirus disease 2019 (COVID-19) also tested positive for SARS-CoV-2 (Rivett et al., 2020). Here, we show that the proportion of both asymptomatic and symptomatic HCWs testing positive for SARS-CoV-2 rapidly declined to near-zero between 25th April and 24th May 2020, corresponding to a decline in patient admissions with COVID-19 during the ongoing UK 'lockdown'. These data demonstrate how infection prevention and control measures including staff testing may help prevent hospitals from becoming independent 'hubs' of SARS-CoV-2 transmission, and illustrate how, with appropriate precautions, organizations in other sectors may be able to resume on-site work safely.

Comprehensive review of mask utility and challenges during the COVID-19 pandemic

Masks are widely discussed during the course of the ongoing COVID-19 pandemic. Most hospitals have implemented universal masking for their healthcare workers, and the Center for Disease Control currently advises even the general public to wear cloth masks when outdoors. The pertinent need for masks arises from plausible dissemination of the SARS-CoV-2 through close contacts, as well as the possibility of virus transmission from asymptomatic, pre-symptomatic, and mildly symptomatic individuals. Given current global shortages in personal protective equipment, the efficacy of various types of masks: N95 respirators, surgical masks, and cloth masks are researched. To accommodate limited supplies, techniques for extended use, reuse, and sterilization of masks are strategized. However, masks alone may not greatly slow down the COVID-19 pandemic unless they are coupled with adequate social distancing, diligent hand hygiene, and other proven preventive measures.

The Phylogeography of MERS-CoV in Hospital Outbreak-Associated Cases Compared to Sporadic Cases in Saudi Arabia

This study compared the phylogeography of MERS-CoV between hospital outbreak-associated cases and sporadic cases in Saudi Arabia. We collected complete genome sequences from human samples in Saudi Arabia and data on the multiple risk factors of human MERS-CoV in Saudi Arabia reported from 2012 to 2018. By matching each sequence to human cases, we identified isolates as hospital outbreak-associated cases or sporadic cases. We used Bayesian phylogenetic methods including temporal, discrete trait analysis and phylogeography to uncover transmission routes of MERS-CoV isolates between hospital outbreaks and sporadic cases. Of the 120 sequences collected between 19 June 2012 and 23 January 2017, there were 64 isolates from hospital outbreak-associated cases and 56 from sporadic cases. Overall, MERS-CoV is fast evolving at 7.43 × 10-4 substitutions per site per year. Isolates from hospital outbreaks showed unusually fast evolutionary speed in a shorter time-frame than sporadic cases. Multiple introductions of different MERS-CoV strains occurred in three separate hospital outbreaks. MERS-CoV appears to be mutating in humans. The impact of mutations on viruses transmissibility in humans is unknown.

Public health might be endangered by possible prolonged discharge of SARS-CoV-2 in stool

•The published data, which showed the COVID-19 patients with low digestive. •manifestation, might be misleading. Case with negative URT test showed positive in. •rectal scarab which challenge the isolation protocol. •As fomite transmission caused clusters of infection of SARS, adequate disinfection. •operations should be adopted in SARS-CoV-2 outbreak.

Rapid assessment of regional SARS-CoV-2 community transmission through a convenience sample of healthcare workers, the Netherlands, March 2020

To rapidly assess possible community transmission in Noord-Brabant, the Netherlands, healthcare workers (HCW) with mild respiratory complaints and without epidemiological link (contact with confirmed case or visited areas with active circulation) were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Within 2 days, 1,097 HCW in nine hospitals were tested; 45 (4.1%) were positive. Of six hospitals with positive HCW, two accounted for 38 positive HCW. The results informed local and national risk management.

Detecting extra-ocular Chlamydia trachomatis in a trachoma-endemic community in Ethiopia: Identifying potential routes of transmission

BACKGROUND

Trachoma elimination efforts are hampered by limited understanding of Chlamydia trachomatis (Ct) transmission routes. Here we aimed to detect Ct DNA at non-ocular sites and on eye-seeking flies.

METHODS

A population-based household survey was conducted in Oromia Region, Ethiopia. Ocular and non-ocular (faces, hands, clothing, water containers and sleeping surfaces) swabs were collected from all individuals. Flies were caught from faces of children. Flies, ocular swabs and non-ocular swabs were tested for Ct by quantitative PCR.

RESULTS

In total, 1220 individuals in 247 households were assessed. Active trachoma (trachomatous inflammation-follicular) and ocular Ct were detected in 10% and 2% of all-ages, and 21% and 3% of 1-9-year-olds, respectively. Ct was detected in 12% (95% CI:8-15%) of tested non-ocular swabs from ocular-positive households, but in none of the non-ocular swabs from ocular-negative households. Ct was detected on 24% (95% CI:18-32%) of flies from ocular-positive households and 3% (95% CI:1-6%) of flies from ocular-negative households.

CONCLUSION

Ct DNA was detected on hands, faces and clothing of individuals living in ocular-positive households suggesting that this might be a route of transmission within Ct infected households. In addition, we detected Ct on flies from ocular-positive households and occasionally in ocular-negative households suggesting that flies might be a vector for transmission within and between Ct infected and uninfected households. These potential transmission routes may need to be simultaneously addressed to suppress transmission.

Mobile phones represent a pathway for microbial transmission: A scoping review

BACKGROUND

Mobile phones have become an integral part of modern society. As possible breeding grounds for microbial organisms, these constitute a potential global public health risk for microbial transmission.

OBJECTIVE

Scoping review of literature examining microbial's presence on mobile phones in both health care (HC) and community settings.

METHODS

A search (PubMed&GoogleScholar) was conducted from January 2005-December 2019 to identify English language studies. Studies were included if samples from mobile phones were tested for bacteria, fungi, and/or viruses; and if the sampling was carried out in any HC setting, and/or within the general community. Any other studies exploring mobile phones that did not identify specific microorganisms were excluded.

RESULTS

A total of 56 studies were included (from 24 countries). Most studies identified the presence of bacteria (54/56), while 16 studies reported the presence of fungi. One study focused solely on RNA viruses. Staphylococcus aureus, and Coagulase-Negative Staphylococci were the most numerous identified organisms present on mobile phones. These two species and Escherichia coli were present in over a third of studies both in HC and community samples. Methicillin-resistant S. aureus, Acinetobacter sp., and Bacillus sp. were present in over a third of the studies in HC settings.

CONCLUSIONS

While this scoping review of literature regarding microbial identification on mobile phones in HC and community settings did not directly address the issue of SARS-CoV-2 responsible for COVID-19, this work exposes the possible role of mobile phones as a 'Trojan horse' contributing to the transmission of microbial infections in epidemics and pandemics.

Evolution and Global Transmission of a Multidrug-Resistant, Community-Associated Methicillin-Resistant Staphylococcus aureus Lineage from the Indian Subcontinent

The evolution and global transmission of antimicrobial resistance have been well documented for Gram-negative bacteria and health care-associated epidemic pathogens, often emerging from regions with heavy antimicrobial use. However, the degree to which similar processes occur with Gram-positive bacteria in the community setting is less well understood. In this study, we traced the recent origins and global spread of a multidrug-resistant, community-associated Staphylococcus aureus lineage from the Indian subcontinent, the Bengal Bay clone (ST772). We generated whole-genome sequence data of 340 isolates from 14 countries, including the first isolates from Bangladesh and India, to reconstruct the evolutionary history and genomic epidemiology of the lineage. Our data show that the clone emerged on the Indian subcontinent in the early 1960s and disseminated rapidly in the 1990s. Short-term outbreaks in community and health care settings occurred following intercontinental transmission, typically associated with travel and family contacts on the subcontinent, but ongoing endemic transmission was uncommon. Acquisition of a multidrug resistance integrated plasmid was instrumental in the emergence of a single dominant and globally disseminated clade in the early 1990s. Phenotypic data on biofilm, growth, and toxicity point to antimicrobial resistance as the driving force in the evolution of ST772. The Bengal Bay clone therefore combines the multidrug resistance of traditional health care-associated clones with the epidemiological transmission of community-associated methicillin-resistant S. aureus (MRSA). Our study demonstrates the importance of whole-genome sequencing for tracking the evolution of emerging and resistant pathogens. It provides a critical framework for ongoing surveillance of the clone on the Indian subcontinent and elsewhere.IMPORTANCE The Bengal Bay clone (ST772) is a community-associated and multidrug-resistant Staphylococcus aureus lineage first isolated from Bangladesh and India in 2004. In this study, we showed that the Bengal Bay clone emerged from a virulent progenitor circulating on the Indian subcontinent. Its subsequent global transmission was associated with travel or family contact in the region. ST772 progressively acquired specific resistance elements at limited cost to its fitness and continues to be exported globally, resulting in small-scale community and health care outbreaks. The Bengal Bay clone therefore combines the virulence potential and epidemiology of community-associated clones with the multidrug resistance of health care-associated S. aureus lineages. This study demonstrates the importance of whole-genome sequencing for the surveillance of highly antibiotic-resistant pathogens, which may emerge in the community setting of regions with poor antibiotic stewardship and rapidly spread into hospitals and communities across the world.

Estimated impact of revising the 13-valent pneumococcal conjugate vaccine schedule from 2+1 to 1+1 in England and Wales: A modelling study

BACKGROUND

In October 2017, the United Kingdom Joint Committee on Vaccination and Immunisation (JCVI) recommended removal of one primary dose of the 13-valent pneumococcal conjugate vaccine (PCV13) from the existing 2+1 schedule (2, 4, 12 months). We conducted a mathematical modelling study to investigate the potential impact of a 1+1 (3, 12 month) schedule on invasive pneumococcal disease (IPD) and pneumococcal community-acquired pneumonia (CAP). Our results and those from a 1+1 immunogenicity study formed the key evidence reviewed by JCVI.

METHODS AND FINDINGS

We developed age-structured, dynamic, deterministic models of pneumococcal transmission in England and Wales to describe the impact on IPD of 7-valent PCV (PCV7; introduced in 2006) and PCV13 (introduced in 2010). Key transmission and vaccine parameters were estimated by fitting to carriage data from 2001/2002 and post-PCV IPD data to 2015, using vaccine coverage, mixing patterns between ages, and population data. We considered various models to investigate potential reasons for the rapid increase in non-PCV13 (non-vaccine serotype [NVT]) IPD cases since 2014. After searching a large parameter space, 500 parameter sets were identified with a likelihood statistically close to the maximum and these used to predict future cases (median, prediction range from 500 parameter sets). Our findings indicated that the emergence of individual NVTs with higher virulence resulting from ongoing replacement was likely responsible; the NVT increase was predicted to plateau from 2020. Long-term simulation results suggest that changing to a 1+1 schedule would have little overall impact, as the small increase in vaccine-type IPD would be offset by a reduction in NVT IPD. Our results were robust to changes in vaccine assumptions in a sensitivity analysis. Under the base case scenario, a change to a 1+1 schedule in 2018 was predicted to produce 31 (6, 76) additional IPD cases over five years and 83 (-10, 242) additional pneumococcal-CAP cases, with together 8 (-2, 24) additional deaths, none in children under 15 years. Long-term continuation with the 2+1 schedule, or changing to a 1+1, was predicted to sustain current reductions in IPD cases in under-64-year-olds, but cases in 65+-year-olds would continue to increase because of the effects of an aging population. Limitations of our model include difficulty in fitting to past trends in NVT IPD in some age groups and inherent uncertainty about future NVT behaviour, sparse data for defining the mixing matrix in 65+-year-olds, and the methodological challenge of defining uncertainty on predictions.

CONCLUSIONS

Our findings suggest that, with the current mature status of the PCV programme in England and Wales, removing one primary dose in the first year of life would have little impact on IPD or pneumococcal CAP cases or associated deaths at any age. A reduction in the number of priming doses would improve programmatic efficiency and facilitate the introduction of new vaccines by reducing the number of coadministered vaccines given at 2 and 4 months of age in the current UK schedule. Our findings should not be applied to other settings with different pneumococcal epidemiology or with immature programmes and poor herd immunity.

Evaluating strategies for control of tuberculosis in prisons and prevention of spillover into communities: An observational and modeling study from Brazil

BACKGROUND

It has been hypothesized that prisons serve as amplifiers of general tuberculosis (TB) epidemics, but there is a paucity of data on this phenomenon and the potential population-level effects of prison-focused interventions. This study (1) quantifies the TB risk for prisoners as they traverse incarceration and release, (2) mathematically models the impact of prison-based interventions on TB burden in the general population, and (3) generalizes this model to a wide range of epidemiological contexts.

METHODS AND FINDINGS

We obtained individual-level incarceration data for all inmates (n = 42,925) and all reported TB cases (n = 5,643) in the Brazilian state of Mato Grosso do Sul from 2007 through 2013. We matched individuals between prisoner and TB databases and estimated the incidence of TB from the time of incarceration and the time of prison release using Cox proportional hazards models. We identified 130 new TB cases diagnosed during incarceration and 170 among individuals released from prison. During imprisonment, TB rates increased from 111 cases per 100,000 person-years at entry to a maximum of 1,303 per 100,000 person-years at 5.2 years. At release, TB incidence was 229 per 100,000 person-years, which declined to 42 per 100,000 person-years (the average TB incidence in Brazil) after 7 years. We used these data to populate a compartmental model of TB transmission and incarceration to evaluate the effects of various prison-based interventions on the incidence of TB among prisoners and the general population. Annual mass TB screening within Brazilian prisons would reduce TB incidence in prisons by 47.4% (95% Bayesian credible interval [BCI], 44.4%-52.5%) and in the general population by 19.4% (95% BCI 17.9%-24.2%). A generalized model demonstrates that prison-based interventions would have maximum effectiveness in reducing community incidence in populations with a high concentration of TB in prisons and greater degrees of mixing between ex-prisoners and community members. Study limitations include our focus on a single Brazilian state and our retrospective use of administrative databases.

CONCLUSIONS

Our findings suggest that the prison environment, more so than the prison population itself, drives TB incidence, and targeted interventions within prisons could have a substantial effect on the broader TB epidemic.

Maximum likelihood estimation of influenza vaccine effectiveness against transmission from the household and from the community

Influenza vaccination is recommended as the best way to protect against influenza infection and illness. Due to seasonal changes in influenza virus types and subtypes, a new vaccine must be produced, and vaccine effectiveness (VE) must be estimated, annually. Since 2010, influenza vaccination has been recommended universally in the United States, making randomized clinical trials unethical. Recent studies have used a monitored household cohort study design to determine separate VE estimates against influenza transmission from the household and community. We developed a probability model and accompanying maximum likelihood procedure to estimate vaccine-related protection against transmission of influenza from the household and the community. Using agent-based stochastic simulations, we validated that we can obtain maximum likelihood estimates of transmission parameters and VE close to their true values. Sensitivity analyses to examine the effect of deviations from our assumptions were conducted. We used our method to estimate transmission parameters and VE from data from a monitored household study in Michigan during the 2012-2013 influenza season and were able to detect a significant protective effect of influenza vaccination against community-acquired transmission.

Transmission of ESBL-producing Enterobacteriaceae and their mobile genetic elements-identification of sources by whole genome sequencing: study protocol for an observational study in Switzerland

INTRODUCTION

Extended-spectrum beta-lactamases (ESBL)-producing Enterobacteriaceae were first described in relation with hospital-acquired infections. In the 2000s, the epidemiology of ESBL-producing organisms changed as especially ESBL-producing Escherichia coli was increasingly described as an important cause of community-acquired infections, supporting the hypothesis that in more recent years ESBL-producing Enterobacteriaceae have probably been imported into hospitals rather than vice versa. Transmission of ESBL-producing Enterobacteriaceae is complicated by ESBL genes being encoded on self-transmissible plasmids, which can be exchanged among the same and different bacterial species. The aim of this research project is to quantify hospital-wide transmission of ESBL-producing Enterobacteriaceae on both the level of bacterial species and the mobile genetic elements and to determine if hospital-acquired infections caused by ESBL producers are related to strains and mobile genetic elements predominantly circulating in the community or in the healthcare setting. This distinction is critical in prevention since the former emphasises the urgent need to establish or reinforce antibiotic stewardship programmes, and the latter would call for more rigorous infection control.

METHODS AND ANALYSIS

This protocol presents an observational study that will be performed at the University Hospital Basel and in the city of Basel, Switzerland. ESBL-producing Enterobacteriaceae will be collected from any specimens obtained by routine clinical practice or by active screening in both inpatient and outpatient settings, as well as from wastewater samples and foodstuffs, both collected monthly over a 12-month period for analyses by whole genome sequencing. Bacterial chromosomal, plasmid and ESBL-gene sequences will be compared within the cohort to determine genetic relatedness and migration between humans and their environment.

ETHICS AND DISSEMINATION

This study has been approved by the local ethics committee (Ethikkommission Nordwest-und Zentralschweiz) as a quality control project (Project-ID 2017-00100). The results of this study will be published in peer-reviewed medical journals, communicated to participants, the general public and all relevant stakeholders.

New insights into transmission of Clostridium difficile infection-narrative review

BACKGROUND

Traditionally, Clostridium difficile has been considered a typical healthcare-associated pathogen-that is, one transmitted within healthcare facilities and thus prevented by implementation of standard infection control measures. Recently this concept has been challenged by studies suggesting a relevant role for community acquisition of C. difficile.

AIMS

To discusses the current literature, compiled during the last decade, reporting on sources of acquisition of C. difficile and subsequent transmission.

SOURCES

The databases PubMed, Medline, Embase and the Cochrane Database were searched for articles published from 1 January 2007 to 30 June 2017 reporting on possible transmission pathways of C. difficile and/or suggesting a source of acquisition of C. difficile. All study types reporting on adult populations were considered; case reports and series were excluded. The PRISMA guidelines for the reporting of systematic reviews were followed.

CONTENT

Among 24 original articles included, 63% report on transmission of C. difficile in healthcare settings and 37% investigate sources and transmission of C. difficile in the community. Contact with symptomatic carriers (53.3%), the hospital environment (40.0%) and asymptomatic carriers (20%) were the most commonly reported transmission pathways within healthcare settings. The leading sources for acquisition of C. difficile in the community include direct contact with symptomatic and asymptomatic carriers in the community, including infants (30%) and residents of long-term non-acute care facilities (30%), followed by contact with contaminated environments in outpatient care settings (20%) and exposure to livestock or livestock farms (20%).

IMPLICATIONS

In healthcare settings, future control efforts may need to focus on extending cleaning and disinfection procedures beyond the immediate surroundings of symptomatic carriers. Potential targets to prevent acquisition of C. difficile in the community include household settings, long-term care facilities and outpatient settings, while the role of livestock in entertaining transmission requires further investigation.

Travel- and Community-Based Transmission of Multidrug-Resistant Shigella sonnei Lineage among International Orthodox Jewish Communities

Shigellae are sensitive indicator species for studying trends in the international transmission of antimicrobial-resistant Enterobacteriaceae. Orthodox Jewish communities (OJCs) are a known risk group for shigellosis; Shigella sonnei is cyclically epidemic in OJCs in Israel, and sporadic outbreaks occur in OJCs elsewhere. We generated whole-genome sequences for 437 isolates of S. sonnei from OJCs and non-OJCs collected over 22 years in Europe (the United Kingdom, France, and Belgium), the United States, Canada, and Israel and analyzed these within a known global genomic context. Through phylogenetic and genomic analysis, we showed that strains from outbreaks in OJCs outside of Israel are distinct from strains in the general population and relate to a single multidrug-resistant sublineage of S. sonnei that prevails in Israel. Further Bayesian phylogenetic analysis showed that this strain emerged approximately 30 years ago, demonstrating the speed at which antimicrobial drug-resistant pathogens can spread widely through geographically dispersed, but internationally connected, communities.

Longitudinal genomic surveillance of MRSA in the UK reveals transmission patterns in hospitals and the community

Genome sequencing has provided snapshots of the transmission of methicillin-resistant Staphylococcus aureus (MRSA) during suspected outbreaks in isolated hospital wards. Scale-up to populations is now required to establish the full potential of this technology for surveillance. We prospectively identified all individuals over a 12-month period who had at least one MRSA-positive sample processed by a routine diagnostic microbiology laboratory in the East of England, which received samples from three hospitals and 75 general practitioner (GP) practices. We sequenced at least 1 MRSA isolate from 1465 individuals (2282 MRSA isolates) and recorded epidemiological data. An integrated epidemiological and phylogenetic analysis revealed 173 transmission clusters containing between 2 and 44 cases and involving 598 people (40.8%). Of these, 118 clusters (371 people) involved hospital contacts alone, 27 clusters (72 people) involved community contacts alone, and 28 clusters (157 people) had both types of contact. Community- and hospital-associated MRSA lineages were equally capable of transmission in the community, with instances of spread in households, long-term care facilities, and GP practices. Our study provides a comprehensive picture of MRSA transmission in a sampled population of 1465 people and suggests the need to review existing infection control policy and practice.

The epidemiology and transmission of methicillin-resistant Staphylococcus aureus in the community in Singapore: study protocol for a longitudinal household study

BACKGROUND/AIM

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common multidrug-resistant organisms in healthcare settings worldwide, but little is known about MRSA transmission outside of acute healthcare settings especially in Asia. We describe the methods for a prospective longitudinal study of MRSA prevalence and transmission.

METHODS

MRSA-colonized individuals were identified from MRSA admission screening at two tertiary hospitals and recruited together with their household contacts. Participants submitted self-collected nasal, axilla and groin (NAG) swabs by mail for MRSA culture at baseline and monthly thereafter for 6 months. A comparison group of households of MRSA-negative patients provided swab samples at one time point. In a validation sub-study, separate swabs from each site were collected from randomly selected individuals, to compare MRSA detection rates between swab sites, and between samples collected by participants versus those collected by trained research staff. Information on each participant's demographic information, medical status and medical history, past healthcare facilities usage and contacts, and personal interactions with others were collected using a self-administered questionnaire.

DISCUSSION/CONCLUSION

Understanding the dynamics of MRSA persistence and transmission in the community is crucial to devising and evaluating successful MRSA control strategies. Close contact with MRSA colonized patients may to be important for MRSA persistence in the community; evidence from this study on the extent of community MRSA could inform the development of household- or community-based interventions to reduce MRSA colonization of close contacts and subsequent re-introduction of MRSA into healthcare settings. Analysis of longitudinal data using whole-genome sequencing will yield further information regarding MRSA transmission within households, with significant implications for MRSA infection control outside acute hospital settings.

Transmission of Mycobacterium Tuberculosis in Households and the Community: A Systematic Review and Meta-Analysis

The individual- and population-level impact of household tuberculosis exposure on transmission is unclear but may have implications for the effectiveness and implementation of control interventions. We systematically searched for and included studies in which latent tuberculosis infection was assessed in 2 groups: children exposed and unexposed to a household member with tuberculosis. We also extracted data on the smear and culture status of index cases, the age and bacillus Calmette-Guérin vaccination status of contacts, and study design characteristics. Of 6,176 citations identified from our search strategy, 26 studies (13,999 children with household exposure to tuberculosis and 174,097 children without) from 1929-2015 met inclusion criteria. Exposed children were 3.79 (95% confidence interval (CI): 3.01, 4.78) times more likely to be infected than were their community counterparts. Metaregression demonstrated higher infection among children aged 0-4 years of age compared with children aged 10-14 years (ratio of odds ratios = 2.24, 95% CI: 1.43, 3.51) and among smear-positive versus smear-negative index cases (ratio of odds ratios = 5.45, 95% CI: 3.43, 8.64). At the population level, we estimated that a small proportion (<20%) of transmission was attributable to household exposure. Our results suggest that targeting tuberculosis prevention efforts to household contacts is highly effective. However, a large proportion of transmission at the population level may occur outside the household.

Molecular, Spatial, and Field Epidemiology Suggesting TB Transmission in Community, Not Hospital, Gaborone, Botswana

During 2012–2015, 10 of 24 patients infected with matching genotypes of Mycobacterium tuberculosis received care at the same hospital in Gaborone, Botswana. Nosocomial transmission was initially suspected, but we discovered plausible sites of community transmission for 20 (95%) of 21 interviewed patients. Active case-finding at these sites could halt ongoing transmission.

Acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in contacts of patients newly identified as colonized or infected with MRSA in the immediate postexposure and postdischarge periods

The acquisition of methicillin-resistant Staphylococcus aureus (MRSA) after exposure to patients colonized or infected with MRSA was assessed. Among contacts with complete surveillance screening, the rate of acquisition was 5.7% and was lower in those identified postdischarge (17/683, 2.5%) compared with those tested in the immediate postexposure period (62/706, 8.8%).

[Relationship between crowding and community acquired skin and soft tissues infections]

The association of the spread of community infections with poverty and overcrowding is well known. In our hospital, located in José C. Paz, we assist sporadic cases of post-cesarean infections caused by community acquired methicillin-resistant Staphylococcus aureus (CaMRSA). In a prospective study of families treated at our hospital, we investigated the relationship between a history of skin and soft tissue infections (SSTI) and extreme overcrowding defined as households with unsatisfied basic needs type 3 (NBI 3). A total of 264 households were included in the study; 109 (41.3%) had a history of SSTI and 59 (22.3%) were NBI 3. A total of 61.0% of the NBI 3 households and 35.6% of the non-NBI 3 households reported SSTI (p = 0.00047). Using Google Maps, we georeferenced households and identified them on a NBI map adapted from the 2010 demographic census. In neighborhoods with NBI > 9.7%, 51.2% of the households had a history of SSTI. When NBI was < 9.7%, the percentage fell to 31.1% (p = 0.0019). These results are suggestive of an association of SSTI acquired in the community with overcrowding and poverty. The presence of CaMRSA in community SSTIs should be suspected. Vancomycin or clindamycin prophylaxis could be considered when cesarean deliveries are performed in women from areas with high NBI or with a history of SSTI.

Risk factors and molecular epidemiology of community-onset, multidrug resistance extended-spectrum β-lactamase-producing Escherichia coli infections

BACKGROUND/AIMS

Although multidrug resistance (MDR) among extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) poses significant therapeutic challenges, little is known regarding the risk factors and epidemiology of community-onset MDR-ESBL-EC infections. We performed this study to investigate risk factors and the molecular epidemiology of community-onset MDR-ESBL-EC infections.

METHODS

We conducted a case-control-control study of community-onset infections. MDR-ESBL-EC was defined as ESBL-EC that demonstrated in vitro resistance to trimethoprim-sulfamethoxazole, fluoroquinolones (FQs), and gentamicin. Patients with MDR-ESBL-EC infections were designated as case patients. A control group I (CG I) patient was defined as a person whose clinical sample yielded ESBL-EC that did not meet the criteria for MDR. A control group II (CG II) patient was defined as a patient with a non-ESBL-EC infection.

RESULTS

Of 108 patients with ESBL-EC infections, 30 cases (27.8%) were due to MDR-ESBL-EC. Compared with CG I, prior use of FQs (odds ratio [OR], 3.16; 95% confidence interval [CI], 1.11 to 8.98) and immunosuppressant use (OR, 10.47; 95% CI, 1.07 to 102.57) were significantly associated with MDR-ESBL-EC. Compared with CG II, prior use of FQs (OR, 15.53; 95% CI, 2.86 to 84.27) and healthcare-associated infection (OR, 5.98; 95% CI, 2.26 to 15.86) were significantly associated with MDR-ESBL-EC. CTX-M-15 was the most common in MDR-ESBL-EC infections (59.1% [13/22]), while CTX-M-14 was the most common in non-MDR-ESBL-EC infections (41.6% [32/77]). CTX-M-15 was significantly associated with MDR-ESBL-EC (59.1% vs. 32.5%, p = 0.028). Pulsed-field gel electrophoresis showed clonal diversity of MDR-ESBL-EC isolates.

CONCLUSIONS

The emergence of strains of MDR-ESBL-EC in the community poses an important new public health threat. More information on the emergence and transmission of these strains will be necessary in order to prevent their spread.

Community-Acquired Infection With Healthcare-Associated Methicillin-Resistant Staphylococcus aureus: The Role of Home Nursing Care

Objective.

To better understand the role of indirect transmission in community-acquired infection with methicillin-resistant Staphylococcus aureus (MRSA).

Design.

Prospective case-control study.

Setting.

A French teaching hospital.

Patients.

A total of 198 case patients and 198 control patients with MRSA or methicillin-susceptible S. aureus infection diagnosed between April 2002 and July 2003.

Results.

Multivariate analysis showed a highly significant independent link between MRSA infection at admission and prior receipt of home nursing care (odds ratio [OR], 3.7; P<.001). Other independent risk factors were prior hospitalization (OR, 3.8; P<.001), transfer from another institution (OR, 2.3; P = .008), and age older than 65 years (OR, 1.6; P = .04). Prior home nursing care showed a frequency dose-response relationship. Eleven MRSA-infected patients had had home nursing procedures but no hospital stay in the previous 3 years. These patients' MRSA strains were related to the prevalent MRSA clone currently spreading in French hospitals.

Conclusion.

Home nursing care appears to be an independent risk factor for MRSA acquisition in the community. The reservoir probably consists of MRSA carriers discharged from the hospital. Community nurses seem to be a potential vector.

The Risk of Nosocomial Transmission of Rift Valley Fever

In 2000, we investigated the Rift Valley fever (RVF) outbreak on the Arabian Peninsula-the first outside Africa-and the risk of nosocomial transmission. In a cross-sectional design, during the peak of the epidemic at its epicenter, we found four (0.6%) of 703 healthcare workers (HCWs) IgM seropositive but all with only community-associated exposures. Standard precautions are sufficient for HCWs exposed to known RVF patients, in contrast to other viral hemorrhagic fevers (VHF) such as Ebola virus disease (EVD) in which the route of transmission differs. Suspected VHF in which the etiology is uncertain should be initially managed with the most cautious infection control measures.

Potential sources of Clostridium difficile in human infection

The view of Clostridium difficile infection as a hospital-acquired infection transmitted only by symptomatic patients is changing. Although C difficile is present in food for human consumption, food-borne infection caused by C difficile has never been confirmed. More information on the infective dose and the level of contamination is needed to determine the risk for food-borne exposure to C difficile in humans. The emergence of C difficile polymerase chain reaction (PCR) ribotype 078 in humans is epidemiologically linked to its presence in piglets and calves and their environment, suggesting zoonotic transmission.

Measles outbreak spreading from the community to an anthroposophic school, Berlin, 2011

Between April and July 2011 there was an outbreak of measles virus, genotype D4, in Berlin, Germany. We identified 73 case-patients from the community and among students of an anthroposophic school, who participated in a 4-day school trip, as well as their family and friends. Overall, 27% were aged ≥ 20 years, 57% were female and 15% were hospitalized. Of 39 community case-patients, 38% were aged ≥ 20 years, 67% were female and 63% required hospitalization. Unvaccinated students returning from the school trip were excluded from school, limiting transmission. Within the group of 55 school-trip participants, including 20 measles case-patients, a measles vaccine effectiveness of 97.1% (95% confidence interval 83.4-100) for two doses was estimated using exact Poisson regression. Our findings support school exclusions and the recommendation of one-dose catch-up vaccination for everyone born after 1970 with incomplete or unknown vaccination status, in addition to the two-dose routine childhood immunization recommendation.

[Cluster outbreak of MRSA in the community; recognition and approach]

BACKGROUND

Community-acquired infection with methicillin-resistant Staphylococcus aureus (CA-MRSA) mainly affects healthy young people, without health-care related risk factors for MRSA. Patients often present with skin and soft-tissue infections.

CASE DESCRIPTION

An 18-year-old woman presented at the casualty department with recurrent purulent skin infections. She proved to be MRSA-positive. Within 6 months, 2 people around her also developed an MRSA infection. Culture showed CA-MRSA, with an identical strain (spa type: t008). Additional screening within her immediate circle identified 4 carriers, 2 of whom had corresponding skin infections.

CONCLUSION

Cluster outbreaks of CA-MRSA require a coordinated approach from both the treating physician and the public health services. The choice of additional investigation among the circle of contacts was the determining factor in breaking the cycle of transmission and reinfection within this cluster.

A data-driven mathematical model of CA-MRSA transmission among age groups: evaluating the effect of control interventions

Community associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a major cause of skin and soft tissue infections (SSTIs) in the US. We developed an age-structured compartmental model to study the spread of CA-MRSA at the population level and assess the effect of control intervention strategies. We used Monte-Carlo Markov Chain (MCMC) techniques to parameterize our model using monthly time series data on SSTIs incidence in children (≤ 19 years) during January 2004 -December 2006 in Maricopa County, Arizona. Our model-based forecast for the period January 2007-December 2008 also provided a good fit to data. We also carried out an uncertainty and sensitivity analysis on the control reproduction number, Rc which we estimated at 1.3 (95% CI [1.2,1.4]) based on the model fit to data. Using our calibrated model, we evaluated the effect of typical intervention strategies namely reducing the contact rate of infected individuals owing to awareness of infection and decolonization strategies targeting symptomatic infected individuals on both [Formula: see text] and the long-term disease dynamics. We also evaluated the impact of hypothetical decolonization strategies targeting asymptomatic colonized individuals. We found that strategies focused on infected individuals were not capable of achieving disease control when implemented alone or in combination. In contrast, our results suggest that decolonization strategies targeting the pediatric population colonized with CA-MRSA have the potential of achieving disease elimination.

First outbreak with MRSA in a Danish neonatal intensive care unit: risk factors and control procedures

Introduction

The purpose of the study was to describe demographic and clinical characteristics and outbreak handling of a large methicillin-resistant Staphylococcus aureus (MRSA) outbreak in a neonatal intensive care unit (NICU) in Denmark June 25^th–August 8^th 2008, and to identify risk factors for MRSA transmission.

Methods

Data were collected retrospectively from medical records and the Danish Neobase database. All MRSA isolates obtained from neonates, relatives and NICU health care workers (HCW) as well as environmental cultures were typed.

Results

During the 46 day outbreak period, 102 neonates were admitted to the two neonatal wards. Ninety-nine neonates were subsequently sampled, and 32 neonates (32%) from 25 families were colonized with MRSA (spa-type t127, SCCmec V, PVL negative). Thirteen family members from 11 of those families (44%) and two of 161 HCWs (1%) were colonized with the same MRSA. No one was infected. Five environmental cultures were MRSA positive. In a multiple logistic regression analysis, nasal Continuous Positive Airway Pressure (nCPAP) treatment (p = 0.006) and Caesarean section (p = 0.016) were independent risk factors for MRSA acquisition, whereas days of exposure to MRSA was a risk factors in the unadjusted analysis (p = 0.04).

Conclusions

MRSA transmission occurs with high frequency in the NICU during hospitalization with unidentified MRSA neonates. Caesarean section and nCPAP treatment were identified as risk factors for MRSA colonization. The MRSA outbreak was controlled through infection control procedures.

Community-associated methicillin-resistant Staphylococcus aureus in college residential halls

Methicillin-resistant Staphylococcus aureus (MRSA) was once a predominantly hospital-acquired organism but community-associated MRSA (CA-MRSA) has become a concern in athletics, prisons, and other nonclinical closed populations. As such, college residential hall occupants and workers may be at elevated risk of spreading or contracting MRSA. Environmental samples were obtained to identify the occurrence of MRSA on surfaces in bathrooms of 15 university residential halls. Sterile swabs and BBL CHROMagar plates were used to sample seven categories of potentially contaminated surfaces in each location. Frequencies and descriptive statistics were prepared. All sites had at least one positive sample for MRSA, and shower floors displayed the greatest prevalence (50%). These results indicate areas for heightened sanitation, and illustrate CA-MRSA potential from such surfaces. The need for hygiene education of affected persons about skin and soft tissue infections like MRSA, and intervention opportunities for public health professionals, are discussed.

Are gym surfaces reservoirs for Staphylococcus aureus? A point prevalence survey

We sought to identify staphylococcal contamination of gymnasium surfaces. Various environmental surfaces were cultured at a university fitness center. Ten out of 99 samples yielded Staphylococcus aureus, all of which were methicillin-susceptible. Gym surfaces may be colonized with staphylococci and could play a role in community transmission of staphylococcal species.

Multidrug-resistant organisms in a community living facility: tracking patient interactions and time spent in common areas

Contact precautions in community living facilities (CLF) are used to reduce the transmission of multidrug-resistant organisms (MDRO). However, this policy does not address the contamination of shared spaces, devices (eg, wheelchairs), and interactions with other patients. Using a real-time surveillance system, this study examines the time MDRO-positive patients spend interacting with others in communal areas. The findings from this study may be used to tailor MDRO policies and practices to the specific needs of CLF.

Risk factors for community-associated Staphylococcus aureus skin infection in children of Maui

The prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection, and Staphylococcus aureus (S. aureus) infection overall, has dramatically increased in the past 10 years. Children and Native Hawaiians and Pacific Islanders (NHPI) are disproportionately affected by CA-MRSA infection. The purpose of this case-control study was to identify risk factors for CA-S. aureus skin infections in children of Maui, Hawai'i, as a foundation for reducing the transmission of these infections. Survey data were obtained from patients in pediatric clinician offices over an 8-month period. NHPI participants were well-represented as 58% of cases and 54% of controls. Chi-square analysis and logistic regression were used to identify risk factors. Significant risk factors predictive of infection among all participants were (a) skin abrasions or wounds, (b) household contact, and (c) overweight or obesity. Risk factors predictive of infection among NHPI were (a) skin abrasions or wounds, (b) antibiotic use within 6 months, (c) overweight or obesity, and (d) a history of eczema or other skin disorder. The role of overweight or obesity in S. aureus skin infections among NHPI has not been identified in previous research and indicates a focus for additional education. Further research is needed to better understand the role of eczema, antibiotic use, overweight and obesity, and socio-cultural factors in these infections.

[Epidemiology and clinical implications of carbapenemase-producing bacteria in Switzerland]

The emergence and global dissemination of carbapenemases represents a major threat to public health. Switzerland has not been spared; we report a case-series of four patients hospitalised in our institution colonised with carbapenemase-producing bacteria. Infections caused by carbapenemase-producing Enterobacteriaceae limit therapeutic options and increase mortality. Detection of carbapenemases is also a challenge for laboratories. It is imperative to implement stringent infection control measures in order to prevent epidemics at the hospital level.

Methicillin-resistant Staphylococcus aureus. A continuing infection control challenge

The ability of MRSA and other staphylococci to colonize, persist, and adapt to multiple environmental and tissue conditions has allowed for these bacteria to be virtually ubiquitous in their distribution. The effectiveness of commonly used antibiotics, such as penicillin, has continued to decline against infections caused by MRSA and increasingly resistant strains. The challenge for both dental and medical health professionals is to routinely apply proven, evidence-based infection control precautions. As mentioned earlier in this discussion, when compliance with effective aseptic technique practices improves, the patients and environments. Ensure that reusable equipment is not used for the care of another patient until it has been appropriately cleaned and reprocessed and that single-use items are properly discarded. Clean and disinfect clinical contact surfaces that are not barrier-protected by using an environmental protection agency-registered hospital disinfectant with a low- (ie, HIV and HBV label claims) to intermediate-level (ie, tuberculocidal claim) activity after each patient. When the surface is visibly contaminated with blood, an intermediate-incidence of detectable infections can be reduced. Microorganisms will continue to evolve and adapt in order to survive and thrive, sometimes at the expense of susceptible human hosts. The struggle is to constantly remain aware of impending infectious threats which may challenge current precautions, and maintain and improve the quality of infection control to minimize the potential for disease.